class_docstr: A strategy with automatic trailing stop-loss, trailing the current
  price at distance of some multiple of average true range (ATR). Call
  `TrailingStrategy.set_trailing_sl()` to set said multiple
  (`6` by default). See [tutorials] for usage examples.
  
  [tutorials]: index.html#tutorials
  
  Remember to call `super().init()` and `super().next()` in your
  overridden methods.
code: def init(self):
      super().init()
      self.set_atr_periods()
  
imports: from collections import OrderedDict
  from inspect import currentframe
  from itertools import compress
  from numbers import Number
  from typing import Callable, Optional, Sequence, Union
  import numpy
  import pandas
  from ._plotting import plot_heatmaps
  from ._stats import compute_stats
  from ._util import _Array, _as_str
  from .backtesting import Strategy
label_desc: Use image node_id 1 for calling the TrailingStrategy obj's underlying member method code with example usage: obj.init() without return types